This invention relates to a gas distributor of a fluidized bed. More specifically, it relates to a means and method for cleaning a gas distributor of a fluidized bed wherein the gas distributor may be subject to fouling, as for instance in a waste heat recovery process.
As the cost of energy increases, it may become economically feasible to recover some usable energy in the form of heat from a waste process stream, wherein the energy was formerly discharged into the environment. An example of a system to accomplish this is a waste heat recovery process. In a waste heat recovery process, a waste process stream having usable heat capacity, such as from an industrial operation, is made to contact a heat recovery means wherein a portion of the usable heat is recovered from the waste process stream. Typically, there may be particulate matter suspended or entrained in and carried along with the waste process stream. An example of a commercial waste heat recovery process is the recovery of heat from a hot combustion stream resulting from the incineration of waste products, such as silicones and solvents used in the manufacture thereof. These waste products can be oxidized to form particles of silicon dioxide and other materials.
The use of a fluidized bed technology is well adapted to heat recovery. A fluidized bed has the capability of operating in temperature ranges up to about 2500.degree.-3000.degree. F. A typical fluidized bed comprises a fluidized bed material supported by a gas distributor. The gas distributor typically has channels or passages through which a gas flows in order to fluidize the material of the fluidized bed. Carried along with the gas may be particulate matter, such as the aforementioned silicon dioxide, a product of the oxidation of silicon. Particulate matter is a source of fouling of the channels of the gas distributor. In order to prevent reduction in size or blockage of the channels, particulate matter which collects in the channels and adheres to the surfaces of the gas distributor must be removed. A prior means for removing such particulate matter from a gas distributor employed a series of wire brushes on a continuous belt which would scrape the underside or gas input side of the gas distributor. The temperature input of the gas stream to the gas distributor was about 700.degree. F.
As a practical matter, it is desirable to provide a means and method for the removal of particulate matter introduced into the gas distributor along with the waste gas stream during a heat recovery process, which are capable of removing particulate matter without having to shut down the heat recovery process and without having to disassemble the gas distributor and fluidized bed. It is also desirable that the removal means and method not materially affect the efficiency of operation of the heat recovery process and be effective over the entire possible operating temperature range of the fluidized bed. Generally, it is only the distributor surfaces on the gas input side which will foul since the material of the fluidized bed tends to scrub the surfaces on the fluidizing side.
It is therefore an object of the present invention to provide a cleaner for a gas distributor of a fluidized bed.
Another object of the present invention is to provide a cleaner for a gas distributor wherein the gas distributor can be cleaned without disassembly.
Another object of the present invention is to provide a cleaner for a gas distributor wherein the gas distributor can be cleaned without stopping the gas flow-through for a heat recovery process.
Still another object of the present invention is to provide a cleaner for a gas distributor wherein the efficiency of the operation of a heat recovery process is not materially affected by the operation of the cleaner.